1. Field of the Invention
The present invention relates to a multilayered ceramic electronic component and, more particularly, to a multilayered ceramic electronic component capable of realizing a reduction in thickness and high reliability (hermetic sealing).
2. Description of the Related Art
An existing multilayered ceramic capacitor (MLCC) having a nickel based internal electrode may generally use copper (Cu) as a base metal for an external electrode and may further include glass.
In an external electrode paste, glass may promote copper sintering and, in addition, may serve as an adhesive to combine the external electrode with a ceramic sintered body, and fill voids, not charged with Cu, thereby completely sealing the voids.
In general, the external electrode paste includes one, two or three types of glass. However, in consideration of typical glass characteristics, in the case in which glass has excellent acid-resistance or favorable capacity contact properties, the glass also has a high softening point, in turn causing degradation in Cu wettability. On the other hand, glass with excellent Cu wettability may exhibit low acid-resistance or weak capacity contact.
A Cu-based external electrode paste in the related art may be prepared by applying a Cu paste containing a single type of glass, or two or three different types of glass, to an external electrode and then drying and calcining the coated electrode, resulting in a final product, that is, a Cu-based external electrode. When a single application or calcination described above is adopted, the glass contained in the Cu paste may have difficulties in satisfying requirements such as adhesiveness between internal electrode and external electrode, sealing of the external electrode, Cu wettability, acid resistance, or the like.
That is, in a case in which a content of silicon oxide, among glass ingredients in the Cu paste, is increased, acid resistance becomes excellent but Cu wettability is degraded and a softening point becomes higher. As a result, the glass may not sufficiently fill an interface and a void in Cu metal.
In contrast, in a case in which a content of silicon oxide decrease, Cu wettability of glass and/or glass transfer to the interface may be sufficiently attained, but movement of the glass toward the interface is too rapid and, therefore, a Cu—Ni alloy may rarely be formed.
Moreover, lack of Cu wettability may cause exudation of the glass on the surface of the electrode after calcination of the electrode.
In order to overcome difficulties in the related art described above, an external electrode paste may be prepared by including two or three types of glass that can solve the above problems. However, in order for respective types of glass to successfully achieve desired functions, they need to be located at a desired position in the external electrode. However, due to the high temperature characteristics of glass, it is difficult to locate the glass at a desired position in external electrode.